Blast Injury to Lung

SIR,-In the cases of crush injury reported in the Journal of March 22 there is evidence to suggest that, whatever the mechanism, the result of the injury is to produce intravascular haemolysis. Many of the patients passed bloodstained urine soon after admission to hospital. Though jaundice has been reported so far the blood bilirubin in the case quoted by Beall, Bywaters, Belsey, and Miles was slightly raised. Prof. Baker has shown' that post-transfusional urinary suppression is due to excretion of haemoglobin with a urine of high acidity and salt concentration. Under these conditions the excreted haemoglobin is converted to a granular deposit of haematin which obstructs the renal tubules. He also showed that, conversely, if the urine be alkaline no haematin granules are formed. Thus it would seem that in these crush injuries more attention might profitably be given to the reaction of the urine, and that the aim of treatment should be to maintain an alkaline urine.-I am, etc., T. DINSDALE, March 29. Surgeon Lieutenant, R.N.V.R.